1. Field of the Invention
The present invention relates to a novel compound and organic light emitting diode using the same, particularly to 9,10-bisphenylphenanthrene derivatives and organic light emitting diode using the same.
2. Description of the Prior Art
OLED works on the principal that electrons and holes diffuse through an electron transport layer (ETL) and hole transport layer (HTL), respectively, to enter a light-emitting layer, and recombine in the emitting region to form a particle generally referred as exciton. In order for the exciton to relax to the ground state, the energy is given off in the form of photo radiation. The radiation color can be tuned by applying different emitting materials. OLED has been highly-regarded due to a lot of advantages, such as self illumination, wider visual angle (>170°), shorter response time (˜μs), higher contrast, higher efficiency, lower power consumption, higher brightness, lower operative voltage (3-10V), thinner size (<2 mm), flexibility and so on.
An exciton generated from recombining a hole and an electron may have triplet state or singlet state for its spin state. The singlet exciton relaxation would radiate fluorescence, and the triplet exciton relaxation would radiate phosphorescence.
In addition, by using a doping method in the emitting layer, self-quenching of the emitting materials can be reduced greatly to enhance the efficiency of the device. Therefore, the search for proper host materials becomes noteworthy since host materials must be capable of capturing carriers and have good energy transfer properties, high glass transition temperature, high thermal stability and appropriate energy gap of the singlet and triplet excited states. However, it would be difficult to search for host materials that fully meet the criteria and there is still some room for host material development in OLED.
Regarding to 9,10-bisphenylphenanthrene derivatives, Japan patent publication No. JP2001-332384A disclosed a 3,6,9,10-tetraphenylphenanthrene having a chemical formula listed below; however, the disclosed 3,6,9,10-tetraphenylphenanthrene still requires improvement in lighting efficiency and thermal stability aspects.

To sum up, it is now a current goal to develop novel host emitters.